Two Sum

Two Sum

LeetCode Problem

• Problem Number: 1
• Problem Link: https://leetcode.com/problems/two-sum/
• Difficulty: Easy
• Topics: Array, Hash Table

Problem Description

Given an array of integers nums and an integer target, return indices of the two numbers in the array that add up to the target.

You may assume that:

• Each input has exactly one solution
• You may not use the same element twice
• You can return the answer in any order

Examples

Example 1:

Input: nums = [2,7,11,15], target = 9
Output: [0,1]
Explanation: Because nums[0] + nums[1] == 9, we return [0, 1].

Example 2:

Input: nums = [3,2,4], target = 6
Output: [1,2]

Example 3:

Input: nums = [3,3], target = 6
Output: [0,1]

Constraints

• 2 <= nums.length <= 10⁴
• -10⁹ <= nums[i] <= 10⁹
• -10⁹ <= target <= 10⁹
• Only one valid answer exists